A total hip replacement procedure has been developed by Howmedica Division of Pfizer Hospital Products, Inc., Rutherford, N.J. and is described in a monograph entitled The P.C.A. Primary Hip System Surgical Technique prepared and published by Pfizer Hospital Products, Inc. in 1988. Howmedica and P.C.A. are registered trademarks of Pfizer Hospital Products, Inc.
The described surgical technique includes implanting an acetabular outer shell or cup prosthesis after appropriately preparing the acetabulum for the implantation. The actual implantation includes orienting, inserting and impacting the acetabular cup in the acetabulum.
Prior to the present invention, a variety of separate instruments have been required to accomplish the implantation. This has been found to be disadvantageous, particularly in view of the time and inconvenience required in switching from one instrument to another, which prolongs the overall operative time. In this connection it will be noted that a major problem encountered in performing surgical procedures such as herein referred to is the risk of infection of the operative area. This risk increases as the operative time increases, and hence it is most desirable to shorten the operative time to the greatest extent possible. Moreover, due to the nature of the procedure, it is imperative that it be performed under circumstances most auspicious to the patient and to the surgeon.
The invention disclosed in the aforementioned copending U.S. application Ser. No. 454,432 overcomes the aforenoted disadvantages and simplifies the implantation, in that only one instrument is required for all of the segments of the procedure. With the instrument therein described, an estimated fifteen to twenty minutes of operative time is saved, which is desirable for the reasons aforenoted.
The invention herein disclosed is an improvement over that disclosed in the referenced co-pending U.S. Application in that a locking arrangement is provided for the several operative members of the instrument thereby facilitating the use thereof, and a more versatile acetabular cup alignment arrangement is provided to accommodate a variety of implantation situations as may from time to time occur.
Accordingly, it is the object of the present invention to provide a single instrument for orienting, inserting and impacting an acetabular cup in a prepared acetabulum as part of a total hip replacement procedure, wherein the use of the instrument is facilitated and the instrument accommodates a wider variety of implantation situations than has heretofore been the case.